Monthly Archives for February 2016

For the first time this year, the Oscars provided a “ticker” that scrolled through all the thank you’s for Oscar winners, allowing them to use their time on stage to discuss something in addition to who they’d like to thank. Lot’s of important, powerful messages were delivered, and here at CauseScience we are very excited that Climate Change happened to be a central theme several times!

And lastly, I just want to say this, making The Revenant was about man’s relationship to the natural world — the world that we collectively felt in 2015 as the hottest year in recorded history. Our production had to move to the southernmost tip of this planet just to be able to find snow. Climate change is real, it is happening right now, it is the most urgent threat facing our entire species, and we need to work collectively together and stop procrastinating.

We need to support leaders around the world who do not speak for the big polluters or the big corporations, but who speak for all of humanity, for the indigenous peoples of the world, for the billions and billions of underprivileged people who will be most affected by this, for our children’s children, and for those people out there whose voices have been drowned out by the politics of greed.

I thank you all for this amazing award tonight. Let us not take this planet for granted; I do not take this night for granted.

In addition to Leo, Mad Max took home about a bazillion Oscars, and several of the Oscar winners also took the time to address climate change in their acceptance speeches. For example, costume designer Jenny Beavan said this in her acceptance speech:

“I just want to say one quite serious thing, I’ve been thinking about this a lot, but actually it could be horribly prophetic, Mad Max, if we’re not kinder to each other, and if we don’t stop polluting our atmosphere, so you know, it could happen,”

Glad to see Oscar winners using their time in the spotlight to highlight the threat of climate change and to urge everyone to do something about it!

In case you didn’t watch the Academy Awards last night – spoiler alert – Leonardo DiCaprio finally won Best Actor for The Revenant! Whether that matters to you or not, Leo continued his vocal stance on climate change and mentioned it in-depth in his acceptance speech!! He also posted about climate change on his Facebook wall, and included MomentForAction.org (below). Check out previous CauseScience posts on Leo killing it in a speech at the UN Climate Summit, and being named UN Messenger of Peace on Climate Change! Leo is definitely the biggest celebrity that continually vocalizes concern for climate change and repeatedly demands action!! Maybe this all started when he realized that Titanic could only happen in a world with icebergs 😉 (FANGIRLING!)

The point is, much is still not known about the possible relationship between the Zika virus and microcephaly. There is evidence that the two conditions are positively correlated within certain areas of Brazil and possibly French Polynesia. While strongly suspected, scientists and health officials have little direct evidence to support a causal link, but that’s due, in part, to the nature of Zika and microcephaly diagnosis. Lastly, Zika does appear to target the brain, but some scientists say much more mechanistic research needs to be done to confirm a causal link between the virus and microcephaly.

In short, much is still unknown about Zika, microcephaly and their possible link. The WHOdeclared the outbreak a public health emergency for precisely this reason — to “coordinate international efforts” to better understand the two conditions’ potential relationship and to control Zika’s spread.

The rumor that GM mosquitoes could be behind the Zika outbreak in Brazil began on Jan. 25 with a Reddit thread titled: “Genetically modified mosquitoes released in Brazil in 2015 linked to the current Zika epidemic?” Some media outlets, including Fox News, The Ecologist and The Daily Mail went on to spread the rumor. Some websites, such as Natural News, cited the involvement of Bill Gates. (The Bill & Melinda Gates Foundation provided $19.7 million for a project to develop and test GM mosquitoes, according to Science.)

However, the stability – that is, the ability to remain balanced – of a bicycle with a rider is more difficult to quantify and describe mathematically, especially since rider ability can vary widely. My colleagues and I brought expert and novice riders into the lab to investigate whether they use different balancing techniques.

The physics of staying upright on a bicycle

A big part of balancing a bicycle has to do with controlling the center of mass of the rider-bicycle system. The center of mass is the point at which all the mass (person plus bicycle) can be considered to be concentrated. During straight riding, the rider must always keep that center of mass over the wheels, or what’s called the base of support – an imaginary polygon that connects the two tire contacts with the ground.

Bicycle riders can use two main balancing strategies: steering and body movement relative to the bike. Steering is critical for maintaining balance and allows the bicycle to move to bring the base of support back under the center of mass. Imagine balancing a broomstick on one hand – steering a bicycle is equivalent to the hand motions required to keep the broomstick balanced. Steering input can be provided by the rider directly via handlebars (steering torque) or through the self-stability of the bicycle, which arises because the steer and roll of a bicycle are coupled; a bicycle leaned to its side (roll) will cause a change in its steer angle.

Body movements relative to the bicycle – like leaning left and right – have a smaller effect than steering, but allow a rider to make balance corrections by shifting the center of mass side to side relative to the bicycle and base of support.

Steering is absolutely necessary to balance a bicycle, whereas body movements are not; there is no specific combination of the two to ensure balance. The basic strategy to balance a bicycle, as noted by Karl von Drais (inventor of the Draisine), is to steer into the undesired fall.

Newbies versus pros

While riders have been described using mathematical equations, the equations are not yet useful for understanding the differences between riders of different ability levels or for predicting the stability of a given rider on a given bicycle.

Therefore, the goal of my colleagues’ and my recent work was to explore the types of control used by both novice and expert riders and to identify the differences between the two groups. In our study, expert riders identified themselves as skilled cyclists, went on regular training rides, belonged to a cycling club or team, competed several times per year, and had used rollers for training indoors. Novice riders knew how to ride a bicycle but did so only occasionally for recreation or transportation and did not identify themselves as experts.

We conducted our experiments in a motion capture laboratory, where the riders rode a typical mountain bike on rollers. Rollers constrain the bicycle in the fore-aft direction but allow free lateral (left-right) movement. They require a bicycle rider to maintain balance by pedaling, steering and leaning, as one would outdoors.

We mounted sensors and used a motion capture system to measure the motion of the bicycle (speed, steering angle and rate, roll angle and rate) and the steering torque used by the rider. A force platform underneath the rollers allowed us to calculate the lateral position of the center of mass relative to the base of support; that let us determine how a rider was leaning.

We found that both novice and expert riders exhibit similar balance performance at slow speeds. But at higher speeds, expert riders achieve superior balance performance by employing smaller but more effective body movements and less steering. Regardless of speed, expert riders use smaller and less varying steering inputs and less body movement variation.

We conclude that expert riders are able to use body movements more effectively than novice riders, which results in reducing the demand for both large corrective steering and body movements.

Mysteries remain

Despite our work and that of others in the field, there is still much to be learned about how humans ride and balance bicycles. Most research, including ours, has been limited to straight line riding, which only makes up a fraction of a typical bicycle ride.

Our work reveals measurable differences between riders of different skill levels. But their meaning is unclear. Are the differences linked to a higher risk of crashing for the novice riders? Or do the differences simply reflect a different style of control that gets fine-tuned through hours and hours of training rides?

Ideally, we would like to identify the measurements that quantify the balance performance, control strategy and fall risk of a rider in the real world.

With such measurements, we could identify riders at high risk of falling, explore the extent to which bicycle design can reduce fall risk and increase balance performance, and develop the mathematical equations that describe riders of different skill levels.